Inspection and ejector unit

ABSTRACT

An inspection and ejector unit for preforms for plastic containers in a transportation line, has at least one driver device which picks up preforms travelling from an inward conveyor device to the inspection and ejector unit, transports them further and passes on at least some of the preforms to an outward conveyor device, at least one detection device by which faulty preforms in the driver device are detected, and at least one ejection device by which preforms which are detected as faulty are removed from the driver device, and a corresponding method.

RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.14/480,886, filed Sep. 9, 2014, which is incorporated herein byreference and which claimed priority on Switzerland Application No.01561/13, filed Sep. 10, 2013, which is incorporated herein byreference.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an inspection and ejector unit forpreforms for plastic containers in a transportation line, and to acorresponding method.

A transportation line having a clamping conveyor for preforms for, forexample, PET bottles, without an inspection and ejector unit, isdescribed, for example, in EP 1 925 575 A1.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a transportation linefor such preforms with a means of reliably detecting and eliminatingfaulty preforms, by which means the transportation flow in thetransportation line is adversely affected as little as possible.

This object is achieved firstly in accordance with the present inventionby an inspection and ejector unit for preforms for plastic containers ina transportation line, comprising at least one driver device which picksup preforms travelling from an inward conveyor device to the inspectionand ejector unit, transports them further and passes on at least some ofthe preforms to an outward conveyor device, at least one detectiondevice by means of which faulty preforms in the driver device aredetected and at least one ejection device by means of which preformswhich are detected as faulty are removed from the driver device, and bya method for detecting and removing faulty preforms for plasticcontainers in a transportation line, having the following steps: (a)picking up preforms, supplied by an inward conveyor device, incorresponding recesses of a driver device, (b) transporting theindividual preforms along a defined distance (S) from the inwardconveyor device in the direction of an outward conveyor device, (c)producing images of the individual preforms in the driver device bymeans of at least one camera of a detection device in a position (P1),preferably at the start of the distance (S), (d) evaluating the imagesof the individual preforms in an evaluation unit of the detectiondevice, (e) transmitting a signal from the evaluation unit to at leastone ejection device if a preform has been detected as faulty, and (f)removing the faulty preform in a position (P2) on the distance (S) whichis located downstream of the position (P1), by means of the at least oneejection device.

In one preferred embodiment of the present invention, the driver deviceis configured in the form of a cam wheel or star wheel which is drivenabout a vertical axis (X). A preform more preferably enters intoengagement with each recess of the cam wheel. In this way, particularlyefficient individuation and precise inspection of the incoming preformscan be achieved. The preforms preferably rest with their collar orsupport ring on the cam wheel, wherein recesses of the cam wheelcorresponding accordingly to the essentially cylindrical part of thepreforms. In other words, the preforms enter into engagement with thecam wheel in an essentially positively locking fashion. Other types ofengagement such as, for example, a (purely) frictional engagement orelse a positive and frictional engagement are however basically alsoconceivable. The preferred drive about the vertical axis is due to thefact that the preforms preferably pass into the inspection and ejectorunit in an upright position (i.e. with the open end upwards).

In a further preferred embodiment of the present invention, thedetection device has at least one camera and one evaluation unit. Withthe camera, the preforms are captured and examined for faults such as anoval shape, collar damage or support ring damage and mouth damage bymeans of image processing methods. In this context, for example acomparison is carried out with setpoint data stored in the evaluationunit for the preforms which are to be respectively inspected. In thecase of a defined difference from the corresponding setpoint data, asignal is then generated in the evaluation unit, which signal istransmitted to the corresponding ejection device in order to eliminateor eject the faulty preform. Depending on the type and number of thecameras used it is possible, in certain circumstances, also to check thesurface condition and the base condition of the preforms.

In another preferred embodiment of the present invention, the ejectiondevice is a pneumatic ejection device which is preferably configured inthe form of an air pipe or else an air nozzle. As a result, the faultyblanks can be reliably ejected in a simple and cost-effective way. Bymeans of the air pipe it is possible, if appropriate, to convey a largerquantity of air than with the air nozzle, while with the air nozzle ahigher air speed can be achieved than with the air pipe. The selectionas to what type of pneumatic ejection device is used depends in eachcase on the circumstances, i.e.

for example on the type, size and the weight of the preforms to beinspected. In general, the use of an air pipe is preferred at present.

In yet a further preferred embodiment of the present invention, theejection device is a mechanical ejection device which is preferablyconfigured in the form of a tappet. Such a mechanical ejection deviceensures equally reliable ejection of faulty preforms with reducedconsumption of air.

In yet another preferred embodiment of the present invention, theejection device ejects the preforms from bottom to top in a verticaldirection. This has proven particularly expedient, economical in termsof time and less susceptible to faults. In this context, a dischargeshaft, by means of which the ejected preforms are discharged, forexample, into a collecting device, is particularly preferably alsoprovided in an aligned arrangement above the ejection device. With theaid of the discharge shaft it is ensured that the ejected preforms donot drop back into the transportation line and cause faults there. Inaddition, the faulty preforms can therefore easily be collected.

Further preferably, the discharge shaft has a U-shaped or arcuateconfiguration as well as an additional air nozzle or else an additionalair pipe. As a result of the U-shaped or arcuate configuration, thefaulty preforms can be quickly directed into a corresponding collectingcontainer. The additional air nozzle or the additional air pipe promotesthe discharging of the faulty preforms. The preforms are thereforecarried through the discharge shaft on an air cushion. In this way, apreform which is ejected can be particularly reliably prevented fromdropping back.

In an alternative embodiment of the inspection and ejector unitaccording to the invention, the ejection device initially lifts up thepreforms from bottom to top in a vertical direction (i.e. withoutalready completely ejecting the latter). This lifting up can take placeby means of a tappet, but preferably an air nozzle is used which outputsa brief vertical pulse of air which lifts up the corresponding preformby a specific distance (preferably by 1 to 2 times its length) so thatit can subsequently be ejected laterally or can pass into acorrespondingly arranged collecting container (i.e. the preform must belifted up at least to such an extent that reliable discharging ispossible without the occurrence of sticking or a blockage). Above thedriver device, a further ejection device is provided for the lateraldischarge, by means of which ejection device the lifted-up preforms areejected or blown out in an essentially horizontal direction in orderthen to be directed into the correspondingly arranged collecting device.A discharge shaft, by means of which under certain circumstancespreforms which have been lifted up to an excessive degree can still bedeflected into the collecting device, is in turn preferably provided inan aligned arrangement above the ejection device/devices. The furtherejection device is preferably arranged in the discharge shaft or in theregion of the discharge shaft, particularly preferably in a side wall ofthe discharge shaft. The further ejection device can be configured as atappet, but an air nozzle is again preferably used, which air nozzleoutputs an essentially horizontal pulse of air. This pulse of air isgenerally longer than the pulse of air of the vertical air nozzle. Thehorizontal air nozzle can have, in particular, a plurality of nozzleopenings; in this way it is possible to ensure that the lifted-uppreforms are reliably conveyed away from the driver device into thecollecting container, since a larger area or larger space can becovered.

In a preferred embodiment of the method according to the invention, theejection according to step (f) takes place in a pneumatic or mechanicalfashion, preferably in a vertical direction from bottom to top, asalready explained above.

In a further preferred embodiment of the method according to theinvention, the preforms are discharged through a discharge shaft whichis provided in an aligned arrangement above the ejection device, whereinpreferably an additional air nozzle or else an additional air pipe,which is activated, under certain circumstances, at the same time as theejection device, is present in the discharge shaft. In this way, it isensured in a particularly effective fashion that the ejected preform isconveyed “seamlessly” through the discharge shaft without the preformbeing able to drop back onto the transportation line or onto the camwheel.

In another preferred embodiment of the method according to theinvention, the driver device has a vertically driven cam wheel, and thedistance (S) describes approximately an arc, preferably an approximately90° arc and particularly preferably an approximately 120° arc. Accordingto this configuration, smooth (further) transportation of the preformsfrom the inward conveyor device (generally a run-off rail) to theoutward conveyor device (generally a clamping conveyor) can be achieved.The camera is arranged here in the starting region of the semicirculardistance (S), i.e. preferably adjacent to the run-in of the preformsinto the cam wheel, for example via the second or third recess of thecam wheel along the distance (S). More preferably, the position (P2) inwhich the faulty preforms are ejected is approximately 30° downstream ofthe position (P1) along the arc. In this way, in all cases asufficiently long “reaction time” remains for the evaluation unit tocheck the image of the respective preform and, if appropriate, output asignal for the ejection of a faulty preform to the ejection device.However, it is also possible to limit the distance (S) over which imagesof the preforms are recorded from the run-off rail up to the outputtingof the non-faulty preforms to the clamping conveyor, for example to acircular arc of less than 90°, if this is necessary, for example, forreasons of space or for other reasons. The camera and ejection devicewould then be correspondingly closer to one another. On the other hand,it is, of course, also possible to lengthen the distance (S) to an arcof approximately 180° or 270°, if this is necessary for reasons of spaceor for other reasons.

In one alternative embodiment of the method according to the invention,the faulty preform is (initially) lifted up from bottom to top in thevertical direction in order then to be ejected in the horizontaldirection, specifically in each case either in a pneumatic or mechanicalfashion (i.e. in each case either by means of a tappet or an airnozzle). In this context, a vertical and (subsequently) an essentiallyhorizontally oriented air nozzle are preferably used, wherein thevertical air nozzle outputs a brief vertical pulse of air onto thebottom of the respective preform, by means of which pulse of air thepreform is lifted up by a specific distance (preferably by 1 to 2 timesits length) with the result that it can be reliably ejected or can passinto the corresponding collecting container (i.e. it must be lifted upat least to such an extent that reliable discharging is possible withoutthe occurrence of sticking or a blockage). Above the driver device, thefurther essentially horizontally oriented ejection device (i.e.generally a horizontal air nozzle) is provided, by means of whichejection device the lifted-up preforms are ejected in an essentiallyhorizontal direction or blown into the correspondingly arrangedcollecting device. The lifting up of the faulty preform preferably takesplace by means of a first pulse of air L1 with a period t1 from theejection device, and the ejection of the faulty preform preferably takesplace t2 by means of a second pulse of air L2 with a period from thefurther ejection device, wherein the period t2 is preferably longer thanthe period t1. This measure also serves to reliably discharge the faultypreform. It has proven particularly reliable if the period t1 of thefirst pulse of air L1 is between 50 and 200 ms, preferably between 80and 120 ms, and the period t2 of the second pulse of air L2 is between 1and 3 s, preferably between 1.5 and 2.5 s.

Furthermore, it has proven particularly expedient if the inspection andejector unit according to the invention is integrated into a clampingconveyor. In this context, for example the non-faulty preforms aretransferred directly from the cam wheel (or, for example, via a bridge)into a belt conveyor device, wherein the collar of the preforms isclamped into corresponding grooves in the belt.

Furthermore, the preforms are preferably conveyed by a run-off rail tothe inspection and ejector unit.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the present invention is illustrated in theappended drawings for the sake of better clarity.

In the drawings:

FIG. 1 shows a plan view of an inspection and ejector unit according tothe invention;

FIG. 2 shows a side view, in particular of a discharge shaft of aninventive inspection and ejector unit with an adjoining collectingcontainer;

FIG. 3 shows a front view, in particular of a discharge shaft and of adetection device of an inspection and ejector unit according to theinvention;

FIG. 4 shows a side view of an exemplary transportation line with thepreferred installation location for the inspection and ejector unitaccording to the invention;

FIG. 5 shows a side view of an alternative embodiment of a dischargeshaft of an inspection and ejector unit according to the invention withan adjoining collecting container; and

FIG. 6 shows a side view of a particularly preferred transportation linewith the respectively preferred installation location for the inspectionand ejector unit according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, firstly a preform 10 is conveyed from the run-offrail 2 to the inventive inspection and ejector unit 1. The cam wheel orstar wheel 8 has recesses 9, by which the preform 10 can be picked upand transported further. The distance which a preform 10 travels in thecam wheel or star wheel 8, i.e. in engagement with one of the recesses9, is denoted by S. At the end of the distance S, the preform 10 istransferred by means of a bridge 5 to a clamping conveyor 3, i.e. to thebelts 4 thereof, which generally have grooves into which the collar ofthe preform 10 is clamped. The cam wheel or star wheel 8 is driven aboutthe vertical axis X.

The incoming preform 10 is therefore conveyed along the distance S bythe recess 9 respectively lying opposite the run-off rail 2. At a firstposition P1 along the distance S, a detection device 6 is arranged here.The detection device 6 generally comprises at least one camera and anevaluation unit. Images of the preform 10 are produced by means of theat least one camera, said images being compared with setpoint values ofa fault-free preform using image processing methods, in order todetermine whether for example oval shapes, support ring damage or collardamage, mouth damage or similar defects are present. If a predefineddeviation, with respect to, for example, the round shape, the conditionof the collar or the mouth condition, is discovered when the comparisonwith the setpoint values of the fault-free preform is carried out, theevaluation unit of the detection device 6 transmits a signal to anejection device 17 which is arranged further downstream from thedetection device 6 along the distance S in the position P2 (cf. FIG. 2).In FIG. 1, the ejection device 17 is, however, not shown since adischarge shaft 7, with which the ejected, that is to say the faulty,preforms 10 are transferred into a corresponding collecting container 16(cf. FIG. 2), is provided above it, in an aligned arrangement.

The distance S describes approximately an arc of 90° from its start toits end. The positions P1 and P2 of the detection device 6 and of theejection device 17 are generally distributed approximately uniformly at30° and 60° (or else 20° and 70°) of the 90° arc. Relatively large andrelatively small arcs with, under certain circumstances, differentdistances are conceivable, depending on requirements.

FIG. 2 illustrates, in particular, the ejection process. The ejectiondevice 17, here in the form of an air pipe, conveys the preform 10,which has been detected as faulty, out of the corresponding recess 9 ofthe cam wheel or star wheel 8 and into the discharge shaft 7 by means ofa pulse of air or an air stream. The ejection process therefore takesplace in a vertical direction from bottom to top. Within the generallyU-shaped discharge shaft 7, the faulty preform 10 is deflected from arounded inner wall 14 of the discharge shaft 7, wherein it issubsequently fed into the collecting container 16 via an (inclined)slide 15, which adjoins the discharge shaft 7 or is part of thedischarge shaft 7. It is apparent that the preforms 10 have anessentially cylindrical body 11, a surrounding collar or support ring 12and a circular mouth 13.

An additional air nozzle 19 or an additional air pipe, with which thedischarge of the faulty preforms 10 can be assisted so that they arecarried through the discharge shaft 7 on an air cushion, can be providedin the discharge shaft 7.

FIG. 3 shows once more a preform 10 coming from the (inclined) run-offrail 2. In the region of the junction with a corresponding recess 9 ofthe cam wheel or star wheel 8, a signaling unit 18 can be provided whichsignals the incoming preforms 10 to the detection device 6. The preforms10 run past underneath the detection device 6 to the ejection device 7or the air pipe where preforms 10 which are detected as being faulty areejected in the vertical direction from bottom to top and pass via thedischarge shaft 7 into the collecting container 16 (cf. FIG. 2). Thefault-free preforms 10 are passed on to the clamping conveyor 3 via thebridge 5. The preforms 10 otherwise rest with their surrounding collar12 (or support ring) on the recesses 9 of the cam wheel or star wheel 8.

Finally, FIG. 4 also illustrates by way of example a transportation linefor preforms 10 in a production line for manufacturing, for example, PETbottles.

In this context, the preforms 10 pass from a feeding device 20 to avertical conveyor 21 which passes on the preforms 10 to a roller sorter22. From there, the preforms pass via a run-off rail 2, now inindividuated form, into the inspection and ejector unit 1 according tothe invention, which is preferably arranged inside the clamping conveyor3. In the clamping conveyor 3, the fault-free preforms 10 are, undercertain circumstances, also rinsed with ionized air and normal air(preferably upside down with vertically positioned air nozzles) andsubsequently passed on to a transfer device 23. Here, the preforms 10are, under certain circumstances, also irradiated with ultraviolet lightbefore they are then passed on to a shaping device 24, for example astretch blow molder.

An alternative embodiment of the present invention is illustrated inFIG. 5. The ejection device 17 (here in the form of an air nozzle or anair pipe) lifts up the preform 10 which has been detected as faulty outof the corresponding recess 9 of the cam wheel or star wheel 8 by meansof a brief, vertical pulse of air L1, with the result that said preform10 can be blown out in an essentially horizontal direction into thecollecting container 16, specifically by means of the pulse of air L2,by the further ejection device 25, which is generally arranged in or inthe region of the side wall 26 of the discharge shaft 7 above the driverdevice 8. In an “essentially horizontal direction” means here that thefurther ejection device 25 or the horizontal air nozzle can also beinclined slightly upward or downward if necessary in order to ensureproblem-free discharging of the faulty preforms 10. The pulse of air L2is generally longer in duration than the pulse of air L1 in order toensure that all the faulty preforms 10 pass into the collectingcontainer 16. The (bent) side wall in which the air nozzle 19 isarranged according to FIG. 2 was omitted in this embodiment and thefurther ejection device 25 is correspondingly arranged on the oppositeside of the discharge shaft 7. The, in turn, U-shaped discharge shaft 7also has again a rounded inner wall 14 in order, under certaincircumstances, to divert, and also direct reliably into the collectingcontainer 16, preforms 10 which, for example in the case of a possiblefault, have experienced an excessively strong vertical pulse of air L1and/or have not experienced any horizontal pulse of air L2. In thisembodiment, an inclined slide 15 is also generally arranged in front ofthe collecting container 16. In this embodiment, the inclined slide hasa horizontal section 27 which extends in the direction of the driverdevice 8 in order to receive the horizontally blown-out preforms 10,with the result that they can be subsequently directed via the slideinto the collecting container 16.

It is again apparent that the preforms 10 have an essentiallycylindrical body 11, a surrounding collar or support ring 12 and acircular mouth 13.

Finally, FIG. 6 illustrates a particularly preferred transportation linefor preforms 10 in a production line for manufacturing, for example, PETbottles. In this context, the preforms 10 pass again from a feedingdevice 20 to a vertical conveyor 21, which passes the preforms 10 on toa roller sorter 22. From there, the preforms pass via a run-off rail2—now individuated—into the inspection and ejector unit 1 according tothe invention (i.e. firstly into the detection device with a camera 6 aand, under certain circumstances, an evaluation unit) which ispreferably arranged inside the clamping conveyor 3 which is configuredhere in an S shape. In the center part of the S-shaped clamping conveyor3 a rinser 28 is provided in which the fault-free preforms 10 (i.e.those which have not been ejected) are rinsed upside down, by means ofvertically positioned air nozzles, with ionized and/or normal air, andsubsequently irradiated in the output region of the clamping conveyor 3with ultraviolet light from an ultraviolet light source 29. The preforms10 are then passed on to a transfer device 23 where, if necessary, theycan be irradiated once more with ultraviolet light before they are thenpassed on to a shaping device 24, for example a stretch blow molder.

LIST OF REFERENCE SYMBOLS

-   1 Inspection and ejector unit-   2 Run-off rail (inward conveyor device)-   3 Clamping conveyor (outward conveyor device)-   4 Belt-   5 Bridge-   6 Detection device-   6 a Camera-   7 Discharge shaft-   8 Cam wheel (driver device)-   9 Recesses-   10 Preform-   11 Cylindrical body-   12 Collar-   13 Mouth-   14 Inner wall discharge shaft-   15 Slide-   16 Collecting container-   17 Ejection device-   18 Signaling unit-   19 Additional air nozzle of the discharge shaft-   20 Feeding device-   21 Vertical conveyor-   22 Roller sorter-   23 Transfer device-   24 Shaping device (stretch blow molder)-   25 Further ejection device-   26 Side wall (of the discharge shaft)-   27 Horizontal section (of the slide)-   28 Rinser-   29 Ultraviolet light source-   X Vertical drive axis-   S Distance-   P1 Position 1-   P2 Position 2-   L1 First pulse of air-   L2 Second pulse of air-   t1 Period of first pulse of air-   t2 Period of second pulse of air

1. An inspection and ejector unit for preforms for plastic containers in a transportation line, comprising at least one driver device (8) which picks up preforms (10) travelling from an inward conveyor device (2) to the inspection and ejector unit (1), transports them further and passes on at least some of the preforms (10) to an outward conveyor device (3); at least one detection device (6) by means of which faulty preforms (10) in the driver device (8) are detected; and at least one ejection device (17, 25) by means of which preforms (10) which are detected as faulty are removed from the driver device (8).
 2. The inspection and ejector unit as claimed in claim 1, characterized in that the driver device (8) is configured in the form of a cam wheel which is driven about a vertical axis (X).
 3. The inspection and ejector unit as claimed in claim 1, characterized in that a preform (10) enters into engagement with each recess (9) of the cam wheel (8).
 4. The inspection and ejector unit as claimed in claim 1, characterized in that the detection device (6) has at least one camera and one evaluation unit.
 5. The inspection and ejector unit as claimed in claim 1, characterized in that the ejection device (17) is a pneumatic ejection device which is preferably configured in the form of an air pipe or else an air nozzle.
 6. The inspection and ejector unit as claimed in claim 1, characterized in that the ejection device (17) is a mechanical ejection device which is preferably configured in the form of a tappet.
 7. The inspection and ejector unit as claimed in claim 1, characterized in that the ejection device (17) ejects the preforms (10) from bottom to top in a vertical direction.
 8. The inspection and ejector unit as claimed in claim 1, characterized in that a discharge shaft (7), by means of which the ejected preforms (10) are discharged, for example, into a collecting device (16), is provided in an aligned arrangement above the ejection device (17).
 9. The inspection and ejector unit as claimed in claim 8, characterized in that the discharge shaft (7) has a U-shaped configuration and comprises an additional air nozzle (19) or else an additional air pipe.
 10. The inspection and ejector unit as claimed in claim 1, characterized in that the ejection device (17) lifts up the preforms (10) from bottom to top in a vertical direction.
 11. The inspection and ejector unit as claimed in claim 10, characterized in that a further ejection device (25), preferably an air nozzle, is provided preferably above the driver device (8), by means of which ejection device the lifted-up preforms (10) are ejected in an essentially horizontal direction.
 12. The inspection and ejector unit as claimed in claim 10, characterized in that a discharge shaft (7) is provided in an aligned arrangement above the ejection device (17), by means of which, under certain circumstances, preforms (10) which have been lifted up to an excessive degree are discharged, for example, into a collecting device (16).
 13. The inspection and ejector unit as claimed in claim 12, characterized in that the further ejection device (25) is arranged in the discharge shaft (7), preferably in a side wall (26) thereof.
 14. A method for detecting and ejecting faulty preforms for plastic containers in a transportation line, having the following steps: (a) picking up preforms (10), supplied by an inward conveyor device (2), in corresponding recesses (9) of a driver device (8); (b) transporting the individual preforms (10) along a defined distance (S) from the inward conveyor device (2) in the direction of an outward conveyor device (3); (c) producing images of the individual preforms (10) in the driver device (8) by means of at least one camera of a detection device (6) in a position (P1), preferably at the start of the distance (S); (d) evaluating the images of the individual preforms (10) in an evaluation unit of the detection device (6); (e) transmitting a signal from the evaluation unit to at least one ejection device (17, 25) if a preform (10) has been detected as faulty, and (f) removing the faulty preform (10) in a position (P2) on the distance (S) which is located downstream of the position (P1), by means of the at least one ejection device (17, 25).
 15. The method as claimed in claim 14, characterized in that step (f) comprises ejecting the faulty preform (10) in a pneumatic or mechanical fashion, preferably in a vertical direction from bottom to top.
 16. The method as claimed in claim 14, characterized in that the preforms (10) are discharged through a discharge shaft (7) which is provided in an aligned arrangement above the ejection device (17), wherein preferably an additional air nozzle (19) or else an additional air pipe, which is activated, under certain circumstances, at the same time as the ejection device (17), is present in the discharge shaft (7).
 17. The method as claimed in claim 14, characterized in that the driver device (8) has a vertically driven cam wheel (8), and in that the distance (S) describes approximately an arc, preferably an approximately 90° arc, particularly preferably an approximately 120° arc.
 18. The method as claimed in claim 17, characterized in that the position (P2) in which the faulty preforms (10) are ejected is at least 30° downstream of the position (P1) along the arc.
 19. The method as claimed in claim 14, characterized in that according to step (f) the faulty preform (10) is lifted up from bottom to top in the vertical direction in order then to be ejected in the horizontal direction, specifically in each case preferably in a pneumatic fashion.
 20. The method as claimed in claim 19, characterized in that the lifting up of the faulty preform (10) takes place by means of a first pulse of air (L1) with a period (t1) from the ejection device (17), and the ejection of the faulty preform (10) takes place by means of a second pulse of air (L2) with a period (t2) from a further ejection device (25), wherein preferably t2>t1.
 21. The method as claimed in claim 20, characterized in that the period (t1) of the first pulse of air (L1) is between 50 and 200 ms, preferably between 80 and 120 ms, and the period (t2) of the second pulse of air (L2) is between 1 and 3 s, preferably between 1.5 and 2.5 s.
 22. A clamping conveyor for preforms for plastic containers, having an inspection and ejector unit (1) as claimed in claim
 1. 